Empire Formation of Ravalli Group of Belt Supergroup (MT*)
Middle Proterozoic*
Type localities are on ridge north of Empire [2 mi west of Marysville] and in canyon walls just below Marysville, Lewis and Clark Co., west-central MT. Named from exposure west of Empire Mine, at head of Lost Horse Gulch in western part of Marysville district, Lewis and Clark Co., west-central MT (Walcott, 1899; see also Knopf, 1950).
Formation was found to be best exposed in section that extends east-west through USGS benchmark 4450 in Scratchgravel Hills, northwest of Helena (see Knopf, 1950).
Northern Rocky Mountain region*
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
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